Re: Re: [PATCH] mm: Add nr_free_highatomimic to fix incorrect watermatk routine
From: Michal Hocko
Date: Mon Sep 02 2019 - 02:10:09 EST
On Mon 02-09-19 13:34:54, ëìì wrote:
> >On Fri 30-08-19 18:25:53, Sangwoo wrote:
> >> The highatomic migrate block can be increased to 1% of Total memory.
> >> And, this is for only highorder ( > 0 order). So, this block size is
> >> excepted during check watermark if allocation type isn't alloc_harder.
> >> It has problem. The usage of highatomic is already calculated at
> >> So, if we except total block size of highatomic, it's twice minus size of
> >> highatomic.
> >> It's cause allocation fail although free pages enough.
> >> We checked this by random test on my target(8GB RAM).
> >> Binder:6218_2: page allocation failure: order:0, mode:0x14200ca
> (GFP_HIGHUSER_MOVABLE), nodemask=(null)
> >> Binder:6218_2 cpuset=background mems_allowed=0
> >How come this order-0 sleepable allocation fails? The upstream kernel
> >doesn't fail those allocations unless the process context is killed by
> >the oom killer.
> Most calltacks are zsmalloc, as shown below.
What makes those allocations special so that they fail unlike any other
normal order-0 requests? Also do you see the same problem with the
current upstream kernel? Is it possible this is an Android specific
> Call trace: